How long for fat and protein to digest?

Okay so I’ve been trying to figure this out for a while now. I am wondering if this may be what is spiking my bg at night. I eat all of my carbs by lunchtime, my blood sugars early in the day are pretty good (80-120) but because my blood sugar is so bad at dinner and nighttime I only eat 5g carbs of veggies and protein for dinner but after dinner my bg is about 140 after exercising 10-20 minutes and then when I check before bed it has increased! Usually about 150-185 and it is sooo frustrating I cannot figure it out! I have been thinking maybe it is my fat and protein I have eaten during the day digesting late…or maybe I just have my highest blood sugar at night… I would love to figure this out or else I think I may need to go on Metformin at nighttime. Any idea why my numbers would be so much worse at night? How long does it take fat and protein to digest and how much does fat and protein increase blood sugar?

Protein can take as long as 6 hours to digest and a fair bit of it can convert to glucose (through Gluconeogenesis). If you are eating a high protein diet, this can affect your blood sugar levels. I have at times eaten 250 g /day, which can be about the equivalent of another 100g of carbs a day spread out.

I rather suspect that JohnG is right, your blood sugar rise may be a response to the exercise. I find that a walk is better than strenuous exercise for burning glucose.

Did you ever clarify your type, LilMama? If you are in fact LADA, you can change your diet and exercise but your numbers will rise.

I seem to digest it pretty slow. If I ingest a lot of fat/protein, my glucose can rise or stay high for 8 to 10 hours. I think it’s one of those cases where YMMV. It’s once case where the pump makes things so much easier. Being able to extend the bolus or temporarily increase the basal rate makes it easier to handle.

It’s not a good idea to segregate your diet so much. Your consumption should be fairly diverse throughout the day. It helps to keep your glucose level.

I’d tend to agree. I fall during exercise, but rise about 20-30 min after I come to rest. A high protein dinner at 7-8pmish will also typically cause a sometimes sharp rise between 10pm-2am. So it could be either, both or something else entirely:)

For me, 4 to 6 hours, depending on how much protein and fat I consume. Pizza, some chinese food, and Thanksgiving dinner always raise my bg for 6 hours.

Good luck Lil MaMa.

About 58% of protein converts to glucose. Dr. Bernstein says it’s more like 30-something percent.

Fat has a very minimal effect on BG, but it does slow down digestion.

Evening is the slowest time for digestion as our bodies are winding down. Difficult because that’s when most of us eat our largest meal. Agree with John that strenuous exercise can send BG high.

I try to keep protein at around the same amount from meal to meal. Helps me stay more level with insulin.